On Wednesday, Dick Marty, the Council of Europe’s special Rapporteur on alleged "illegal activities" of the CIA in Europe, submitted a "draft report" on the matter. The following from a related article in Thursday’s edition (8 June) of the Frankfurter Allgemeine Zeitung (FAZ):

According to the conclusions of a Council of Europe investigation on illegal activities of the CIA in combating terrorism, it is highly probable that the American intelligence agency had installations used for interrogating prisoners in at least two of the 46 member states [of the Council of Europe]: Poland and Romania. In the opinion of Dick Marty, the special Rapporteur of the Parliamentary Assembly of the Council of Europe, the indications of this are so conclusive [schlüssig], that the burden of proof is reversed.

This is to say that, according to Marty, Poland and Romania must now prove that their territories did not house such installations: needless to say, a logically-impossible task. Here the FAZ further on Marty’s "conclusive indications" (sic.):

Marty can show, for instance, that the same CIA plane that in January 2004 presumably brought [Khaled Al-] Masri to Kabul, then on the return journey stopped in Timisoara in Romania before continuing on to Palma de Mallorca for a rest stop. A similar flight can be shown to have been made in September 2003 to the Polish Air Force base Szymany near Szczytno; a large installation of the Polish secret service is also supposed to be found in the area. Whereas some airports in Europe were used by the CIA to refuel or for stopovers,…Marty comes to the conclusion that prisoners from Kabul were deposited during the landings in Timisoara and at the Szymany base.

Note that Szymany is in fact a regional airport, not a Polish Air Force base, though the Marty report insinuates – again on the basis of a vague "indication" (§67), not proof – that it was used at the time for defense purposes. For the full Marty report, see here [pdf-file in English] on the Council of Europe site. And for background on the Khaled Al-Masri case, which is central to Marty’s allegations, see here on Trans-Int.